Circular knitting machine

ABSTRACT

A circular knitting machine with a needle cylinder ( 11 ), in which cylinder needles ( 13 ) are mounted to be longitudinally displaceable, and a dial ( 12 ), in which rib dial needles ( 14 ) are mounted to be radially displaceable, wherein auxiliary elements ( 15 ), in particular sinkers, associated with the cylinder needles ( 13 ) and auxiliary elements ( 16 ), in particular sinkers, associated with the rib dial needles ( 14 ), as well as separate thread feeds to the cylinder needles ( 13 ) and to the rib dial needles ( 16 ) are provided, wherein separate tubular knits ( 19, 20 ) can be produced simultaneously or one after the other with the cylinder needles ( 13 ) and with the rib dial needles ( 14 ).

Nowadays modern circular knitting machines reach speed factors(=diameter×number of revolutions) of up to SF=1500. However, there arelimits to a further increase in the speed factor because of the highneedle abrasion. The present speed factors can already only be reachedby restricting the path of movement of the needles using relativelymovable sinkers and the flattest possible rounded cams for the needlebutts. Further optimisations can be achieved by appropriate needlegeometry and the development of new needle materials. Nonetheless,reaching speed factors above SF=2000 is highly improbable.

The object forming the basis of the present invention is to furtherincrease the productivity of known circular knitting machines withstructurally simple measures.

The object is achieved by a circular knitting machine with a needlecylinder, in which cylinder needles are mounted to be longitudinallydisplaceable, and a dial, in which rib dial needles are mounted to beradially displaceable, which is characterised in that auxiliaryelements, in particular sinkers, associated with the cylinder needlesand auxiliary elements, in particular sinkers, associated with the ribdial needles, as well as separate thread feeds to the cylinder needlesand to the rib dial needles are provided, and that separate tubularknits can be produced simultaneously or one after the other with thecylinder needles and with the rib dial needles.

With the circular knitting machine according to the invention tubularknits can be produced on the cylinder and on the dial at the same time,as a result of which productivity is doubled in comparison toconventional knitting machines. A knitting machine according to theinvention would correspond to a conventional machine with a speed factorof SF=3000. In this case, the two tubular knits can be knittedidentically or differently, e.g. in different colours. The thread feedscan be formed by a joint thread guide with multiple eyelets or bymultiple separate thread guides.

However, it is also possible with the circular knitting machineaccording to the invention to produce the two tubular knits one afterthe other on the cylinder and on the dial.

This is particularly advantageous if different knits, in particularknits of different fineness, are to be produced with the cylinderneedles and with the rib dial needles.

There also results a productivity advantage over conventional machineswhen knitting the two tubular knits one after the other, since the twoqualities of tubular knits can be knitted one after the other and in anydesired alternation without any interim refit of the machine.

Moreover, it is conceivable to use a dial with a smaller diameter thanthe needle cylinder, so that two knits of different diameter can beproduced on the machine.

The circular knitting machine according to the invention can, of course,also be operated as a conventional machine, which produces a tubularknit only on the cylinder. The production of a knit exclusively on thedial is also possible.

The removal of the produced webs can be performed in different ways.

Thus, the tubular knits formed by the cylinder needles and the rib dialneedles can be removable jointly by a removal device or by separateremoval devices.

Knitted webs produced simultaneously on the cylinder and on the dial lieone inside the other. A joint removal device equipped with a spreaderand with a cutting device on both sides can be provided for these. Theproduced knits can then be wound onto a double winder as four flat-lyingwebs.

Alternatively, a joint removal device can be provided, which has an openframe and a cutting device on one side. The two tubular knits lying oneinside the other are cut open on one side and spread. They are thenwound as two wide, flat-lying webs by a withdrawal winding roller.

However, the circular knitting machine can also have a removal devicewith an open frame and a removal device without an open frame. Thisallows one tubular knit to be wound up directly and the other tubularknit to be cut open, spread and wound as flat-lying web.

In contrast, in a further configuration of the circular knitting machineone or two folding devices are provided for the produced tubular knits.If four fabric webs are produced by cutting open the tubular knits onboth sides, then four folding devices can also be provided.

All known techniques for circular knitting machines can be used for thestitch-foil ling process on the needle cylinder and on the dial.

In a preferred embodiment of a circular knitting machine according tothe invention, on a raising movement of the cylinder needles duringstitch formation the associated auxiliary elements configured as sinkersperform a retraction movement and perform a raising movement on awithdrawing movement of the cylinder needles during stitch formation.Very high knitting speeds can be reached as a result of this relativemovement between the needles and the auxiliary elements, since theneedles only need to perform approximately half the reciprocatingmovement in comparison to machines with fixed sinkers or sinkers thatmove with the needles in the same direction.

This technique can also be applied in principle in the case of the dial.Thus, on a raising movement of the rib dial needles during stitchformation the associated auxiliary elements configured as sinkersperform a retraction movement and on a retraction movement of the ribdial needles during stitch formation the associated auxiliary elementsperform a raising movement.

It is, of course, particularly preferred to provide this relativemovement between the needles and the auxiliary elements both on thecylinder and on the dial. The machine can then be operated at maximumnumber of revolutions.

While the auxiliary elements are preferably configured as sinkers, latchneedles, compound needles or bearded needles can be used as needles.

Further advantages can be achieved if cylinder cam segments areprovided, which have needle cams for controlling the raising andwithdrawing movement of the cylinder needles and sinker cams, with whichthe auxiliary elements for the cylinder needles can be caused to performvertical movements and/or a swivelling movement around a horizontalaxis. As a result, the auxiliary elements act as knock-over orholding-down sinkers and assure a reliable stitch formation.

Analogously, dial cam segments can be provided, which have needle camsfor controlling the raising and retraction movement of the rib dialneedles and sinker cams, with which the auxiliary elements for the ribdial needles can be caused to perform radial movements and/or aswivelling movement around a horizontal axis. Because of the necessaryradial movement at least of the rib dial needles, the configuration ofthe dial cam segments is clearly more complex than the configuration ofthe cylinder cam segments. This applies all the more, the smaller thediameter of the dial.

Preferably, the auxiliary elements are also mounted respectively in theneedle cylinder and the dial. They can thus be controlled jointly withthe needles of corresponding cylinder and/or dial cam segments. However,the auxiliary elements can also be mounted in separate devices likesinker rings. Control of the movement of the auxiliary elements in thedial by means of the dial cam segments is particularly demanding in thiscase. The auxiliary elements must be radially moved and swivelled.

In an alternative configuration of the machine the auxiliary elementscan also be fixed knock-over bits. Cam parts or other drive devices formoving the auxiliary elements can be omitted in this configuration.

In addition, the cylinder needles and/or the rib dial needles can beconfigured as bearded needles and the associated auxiliary elements canbe configured as beard-closing elements. Circular knitting machines withcorrespondingly configured cylinder needles are known, for example, fromGB 188449 A1 or GB 114144 A1.

In a further preferred configuration of the circular knitting machinethe dial can be height-adjustable and the auxiliary elements and thethread feed to the rib dial needles or the thread feed to the cylinderneedles can be rendered inoperative, so that a fine rib tubular knit canbe produced jointly with the cylinder needles and with the rib dialneedles.

With the machine equipped in such a way doubled single-sided tubularknits or double-face knits such as fine rib knits can be produced. It ispossible to convert the machine to different modes of operation withoutsubstantial expenditure in this case. Therefore, the customer has thechoice between the production of single-face goods with highproductivity or the production of double-face goods.

A possible exemplary embodiment of a circular knitting machine accordingto the invention is described in more detail below with reference to thedrawing.

FIG. 1 is a schematic partial view of a needle cylinder and a dial of acircular knitting machine according to the invention;

FIG. 2 is a view corresponding to FIG. 1 of the circular knittingmachine with lowered dial;

FIG. 3 is a detail view of a cylinder cam part of the circular knittingmachine from FIG. 1;

FIG. 4 is a detail view of a dial cam part of the circular knittingmachine from FIG. 1.

The detail view of a circular knitting machine 10 in FIG. 1 shows aneedle cylinder 11 and a dial 12. Cylinder needles 13 are mounted to belongitudinally displaceable in the needle cylinder 11. Each needle 13has an associated auxiliary element 15 in the form of a sinker forstitch formation. Analogously, rib dial needles 14 and associatedauxiliary elements 16 in the form of sinkers are mounted in the dial 12.

A thread 17, 18 is fed respectively to both the cylinder needles 13 andto the rib dial needles 14. A first tubular knit 19 is produced fromthread 17 by means of the cylinder needles 13. The rib dial needles 14at the same time form a second tubular knit 20 from thread 18, whichlies within the first tubular knit 19 and is removed together with this.Therefore, with the represented circular knitting machine 10 double theamount of fabric can be produced at the same time as on conventionalcircular knitting machines. It is, of course, also possible to producethe tubular knits 19 and 20 one after the other. In this case, thetubular knits 19 and 20 can even be produced in different finenessqualities, patterns and colours.

While FIG. 1 shows the circular knitting machine 10 with a dial 12raised in relation to the needle cylinder 11, machine 10 in FIG. 2 isrepresented with the dial 12 in a lowered position. The sinkers 15 and16 are in a non-operating position. Only one thread 17 is fed, fromwhich the cylinder needles 13 and the rib dial needles 14 jointlyproduce a fine rib tubular knit 21.

Thus, as a result of the vertical adjustability of the dial 12 inrelation to the needle cylinder 11, separate tubular knits 19, 20 or ajoint double-faced tubular knit 21 can be produced with the circularknitting machine either on the needle cylinder 11 or the dial 12.

FIG. 3 shows a detail drawing of a cylinder cam segment 30 of thecircular knitting machine 10 from FIG. 1. The movements of the cylinderneedles 13 and the sinkers 15 are controlled with the cam segment 15. Aneedle control cam 32, into which the needles 13 engage with a butt 33,is provided to control the vertical movements of the needles 13 in thedirection of double arrow 31.

The sinkers 15 perform vertical movements in the direction of doublearrow 34 as well as a swivelling movement around a butt 35. The butt 35is mounted in a control cam 36, which controls the vertical movements.Upper and lower swivel cams 37, 38 are provided for the swivellingmovement. In this case, the cam segment 30 is configured in such a waythat the needles 13 and the sinkers 15 are movable relative to oneanother, i.e. the sinkers 15 are retracted during a raising movement ofthe needles 13 and raised and swivelled during a retraction movement ofthe needles 13. This leads to relatively small vertical movements ofboth the needles 13 and the sinkers 15, which allows very high machinespeeds.

FIG. 4 shows a dial cam segment 40 of the circular knitting machine 10from FIG. 1 configured in a similar manner to the cylinder cam segment30. The rib dial needles and the associated control cam for their radialmovements have been omitted from this drawing for reasons of clarity.

The cam segments 40 are arranged above the dial 12 and have a firstcontrol cam 41 for the radial movement of the sinkers 16 on theirunderside. The sinkers 16 also perform swivelling movements, which arecontrolled by a front and a rear swivel cam 41, 43. In this case, thecentre of rotation for the swivelling movements lies in the control cam41. The dial cam segments 40 are also configured in such a way that therib dial needles 14 and the sinkers 16 perform relative movements inorder to shorten the relative movements of the needles.

The circular knitting machine shown in FIGS. 1 to 4 is merely a possibleexemplary embodiment of a circular knitting machine according to theinvention. Compound needles or bearded needles could also be used inplace of the shown latch needles 13 and 14. The auxiliary elements 15and 16 do not have to be sinkers, instead they can also be configured asbeard-closing elements, for example. Moreover, it is possible to arrangethe auxiliary elements 15, 16 outside the needle cylinder 11 and thedial 12. The simultaneous formation of knits on the needle cylinder andthe dial is also possible with such variants.

1. A circular knitting machine, comprising: a needle cylinder in which cylinder needles are mounted to be longitudinally displaceable; a dial upon which rib dial needles are mounted to be radially displaceable; first auxiliary elements embodying sinkers, associated with the cylinder needles; second auxiliary elements embodying sinkers, associated with the rib dial needles; and separate thread feeds to the cylinder needles and to the rib dial needles; wherein separate tubular knits can be produced simultaneously or one after the other with the cylinder needles and the rib dial needles.
 2. The circular knitting machine according to claim 1, wherein identical knits or knits in different fineness, can be respectively produced with the cylinder needles and with the rib dial needles.
 3. The circular knitting machine according to claim 1, wherein the tubular knits formed by the cylinder needles and the rib dial needles are removable jointly by a removal devise or by separate removal devices.
 4. The circular knitting machine according to claim 3, further comprising a removal device equipped with a spreader and with a cutting device on both sides.
 5. The circular knitting machine according to claim 3, further comprising a removal device with an open frame and a cutting device on one side.
 6. The circular knitting machine according to claim 3, further comprising a first removal device with an open frame and a second removal device without an open frame.
 7. The circular knitting machine according to claim 3, further comprising one, two or four folding devices for produced tubular knits.
 8. The circular knitting machine according to claim 1, wherein on a raising movement of the cylinder needles during stitch formation, the associated first auxiliary elements embodying sinkers perform a retraction movement and that on a withdrawing movement of the cylinder needles during stitch formation the associated first auxiliary elements perform a raising movement.
 9. The circular knitting machine according to claim 1, wherein on a raising movement of the rib dial needles during stitch formation the associated second auxiliary elements embodying sinkers perform a retraction movement and that on a retraction movement of the rib dial needles during stitch formation the associated second auxiliary elements perform a raising movement.
 10. The circular knitting machine according to claim 1, further comprising cylinder cam segments with needle cams for controlling the raising and withdrawing movement of the cylinder needles and sinker cams, with which the first auxiliary elements for the cylinder needles can be controlled to perform vertical movements, a swivelling movement or both around a horizontal axis.
 11. The circular knitting machine according to claim 1, further comprising dial cam segments, which have needle cams for controlling the raising and retraction movement of the rib dial needles and sinker cams, with which the second auxiliary elements for the rib dial needles, can be controlled to perform radial movements, a swivelling movement or both around a horizontal axis.
 12. The circular knitting machine according to claim 1, wherein the first and second auxiliary elements are mounted respectively in the needle cylinder and the dial or in separate devices.
 13. The circular knitting machine according to claim 1, wherein the first and second auxiliary elements are fixed knock-over bits.
 14. The circular knitting machine according to claim 1, wherein the cylinder needles, the rib dial needles or both are configured as bearded needles and the associated first and second auxiliary elements are configured as beard-closing elements.
 15. The circular knitting machine according to claim 1, wherein the dial is height-adjustable and the first and second auxiliary elements and the thread feed to the rib dial needles or the thread feed to the cylinder needles can be rendered inoperative, so that a fine rib tubular knit can be produced jointly with the cylinder needles and with the rib dial needles. 